As influenza vaccine efficacy is reported to be lower in elderly subjects compared to healthy adults, probably as a result of immunosenescence, there is a desire to devise ways to increase the current vaccines efficacy for this target population. Adjuvants are known to boost immune responses, thus representing one way to increase the efficacy of the current GlaxoSmithKline Fluarix™ influenza vaccine in elderly subjects. The purpose of this study is to evaluate the immunogenicity and the reactogenicity of a vaccination with four different adjuvanted GlaxoSmithKline influenza vaccines administered to elderly subjects. For immunogenicity and safety evaluations, healthy adults aged 18 to 40 years old and elderly aged 65 years and older will receive Fluarix™ and form the control groups of this trial.